Means for compensating for disturbances of earth potential.



P. J. HOWE. MEANS FOR COMPENSATING FOR DISTURBANCES 0F EARTH POTENTIAL.APPLICATION FILED MAR. 10, 1917.

1,254,910, Patented Jan. 29,1918.

ATTORNEY PAUL'J. HOWE, OF RIDGEWOOD, NEW JERSEY, ASSIGNOR TO THE WESTERNUNION v TELEGRAPH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

MEANS FOR COMPENSATING FOR DISTURBANOES OF EARTH POTENTIAL.

Specification of Letters Patent.

Patented J an. 29, 1918.

Application filed March 10, 1917. Serial No. 153,830.

tion, such for example as a telegraph system, and comprises. a generatorlocated in one of the ground connections of the system, togetherwithnovel control means for that generator, and other features all ashereinafter described-and particularly pointed out in the appendedclaims.

The obJect of my invention is to provide simple and reliable means forcompensating for differences of potential between the grounds at the twoends of a system of communication, and to avoid any periodic-oscillationof potential due to the action of the compensating means itself.

I will now proceed to describe my invention with reference to theaccompanying drawings, in which Figure 1 is a diagram illustrating acompensating arrangement embodying my invention, in connection withsystems of communication extending between the points between which thedifferences of potential exist; and Fig. 2, is a fragmentary diagramillustrating an alternative arrangement. Fig. 3 is a fragmentary diagramillustrating a further alternative arrangement.

In the operation of telegraph systems, telephone systems and the like,much trouble is frequently experienced due to a differ ence of potentialbetween the grounding points of the system, which difference ofpotential is commonly due to neighboring electric railways or electricpower circuits or the like. This difference of potential,

due to causes external to the system of communication, is frequentlyvariable, which makes correction for such difference of potential byordinary means, yet more dithcult. By the present invention suchdifiiculty is overcome.

.lln the accornaanvin drawin s l and 2 designate groui'iding bus-bars atthe two points between which the dilierence of earth potential exists;and 3 and 4 designate the line wires of systems of communicationextending from the one bus-bar to the other. At the ends of theseconductors 3 and 4 I have shown, diagrammatically, the transmitting andreceiving arrangements of ordinary duplex telegraph systems, suchtransmitting and receiving arrangements being too well known to requiredescription here. The systems of communication of wires 3 and 4 areentirely separate and distinct, and there may be as many of thesesystems between bus-bars 1 and 2, as desired; nor need these systems ofcommunication be of the same nature; that is to say, one might be atelegraph system and the other or others telephone systems;

- 5 designates an earth connection for bus-,- bar 1, and 6 designates agenerator interposed in that ground connection, 7 and 7 being thefieldwindings of that generator. 8 designates the ground connection forbusbar 2. It will be apparent that generator 6, if properly controlledandoperated, will create a potential, equal and opposite to the earthpotential existing between groundv connections 5 and 8, so neutralizing,or compensating for, the actual difference in earth potential betweenpoints 5 and 8.

9 designates a polar relay having magnet windings 10 located in aconductor 12 leading from bus-bar 1 to some point- 13 in which nopotential disturbance exists. This point 13 is usually a pointlocatedlaterally with respect to conductors 3 and i; that is to say, itis not usually a point which is either in a direct line between points 1and 2, or a oint close to the line conductors 3 and 4.

lhis relay 9 differs from ordinary polar relaysin that, instead of itsarmature 11 playing between contact stops, as is ordi-' narily the case,that armature lever operates variable resistance devices 14 of a natureanalogous to, andeven identical with, the ordinary telephone microphone,and these variable resistance devices are represented diagrammaticallyby the conventional designation for a telephone microphone. The actualmovements of the armature lever 11 are, naturally, extremely small; butwhen the armature lever is attracted in the one direction or the other,it increases the pressure in the microphone toward which lever 11 ispulled, and correspondingly defield soils Tend.

connected to the armsiure ll since in the opposi YDlFlOjJilOllQ. The dof -the generator eoiiipi'ises {lil'fereniiai y and 7 respectively, andii wound coils equal (IHTQ-YWJS pass through 'l ese two coils 7 and '7said. ewe coils neutralize each other. A beiiery 15 01 other likablesource of cm rent supply has one pole eonnee'ecl between she-Se cells '7and 7E and its other pole h. A i-esist'nee devices is causing field.soils,

Q and 7 io iieiitislize each other; but SilO'Lli ii 'iiei'e be CiL,

Terence of potential bezfiieeii loos-see i sml grounding point 13 therewil Be s Ties 05: current, in

the one eiirseiioe. o; the ollzes, es the case of rearms-- the other,soeoreliiig so the dlifesiiifliil 1 rem iioi', so inereasi eondeefiivitvlike one vsriable 1e. decreasing, the conduct; vsrielile resisicaiieedevice one of the m pi' poxicleicsile in infilieiiee over the oi '1"said field coil, txereby giving so the ii s iiiegnetissiioii which willcause genexslei' *5 build o a poiential of e and value cause 1i) tocounterbalance the disturbance sires-fly It will obvious the relay 9will follow and will iiie eomiueafiivity of its veiieble devices inCGFTE sponclei ee wish each elisizge of potemkisi ciifierenee beaweenbiis-lmi 1 end. grounding point 13, shes ceiisinggenei'e'ior S toinmay be tnieogli toe magnet soils ley 9 Y more lever 1L fielwe silo 31e sfoanfiy correspond in vol and, sign of the poteseiel created 03'eoiimtei'balsince, she changing so be- ?zween 1 and 13. v

Various circuit srmngements involving the use of the verisiileresistance reioy 9 may be devised. in Fig 2 1 show on arrange-- mentwherein, instead of one battery sml two difiei'entially Wound fieldcoils Z and 7 two opposing batteries 15 and 15* ere employecl, with onefield coil T; s iilsble fwsistsnee being employed in series with theseveral batteries to adjust the current strengths. will obvious that, asshe why 9 operates, the semen": of one battery mm 1w h Jili :Ju

to mepeiidemse over s lzstiiei'y, smi therefore the lie field coil 7"Will be i, the other, according to the direction in Wl'eii the arrestis Ill of relay i9 is eii'zrsctecl, the strength 01 the current soflowing through i'il 1e field coil 7 depenoling upon i119, strength ofthe current in circuit 12 tending to move the armature ill in the onedirection or the osiier, As illusirated in Fig, 3, the conductor 12, in.which the relay 9 located, is not necessarily 2i (IGZlUiUCiZQl leadingto point external to the system and. free i om poiential. disturbance;but may be a eonoiicsor connecting the two bil$-bif$ l and 2 the systemThe means herein described fol eompeneating for poizentiel disturbanceis not confined to compensating for di'i'eel current po teniioidisturbance, but is siso applicable for correction for eitherslim-eating, current ground potential disturbance, or or {killernstingmiriieni; electromagnetic indueiion. in eoi'npsnion ei ipliestion byJoseph W. li'Liiil1Oi Sesial No, 1523 825, Mr. ii lilnoi has illustratesand describes means for someotiote. lei slieirest current disturbancessuch as iei'ei'i'ecl so, comprising one or more correcting alternatingcurrent generators arranged to oppose the influence of oihei' potentiniiii the line to the disturbing potential, eon'ipi'ising 1 eonitrei Wire,correspom. 0' substantially to the conductor 12,

of ilie present s 'iplicetion, current through I which control Wire,fine so iincoi'i'eeiecl or over-corrected sissy-eating eurrendisturbance operates relay means Wli i'eby the @0lrectii'lg generator orgenerators is or are controlled, in effect proper eosreetion. Theparticnisr control means herein illustrated and described is adapted tobe substituted in the arrangements of the saicl Miinor application, forthe control relays and associated means of thee Milnor sppliemtion, and.the relations of else two applications is such that this substitution isof an obvious neigui'e.

What I claim is:

l lliiezins for compensating fol? poieiisiel- (listoosnee in systems or?eommonicmfiion compi'ising a generator connected in the systemcommunication {no oppose e sounsersclaiiw potential to the disturbingposes tisl, conductor exposed. to the disturbing influence of thediseiirbing" polzeii eiel a polar relay interposed insucle conductorencl comprising variable resisleece means arranged;

we be opemieil by such yelsy, and means operated by such variableresistance means whereby, as said relay is operated. in one direction oranother by e disim-loing potential, the field of the generator is ezcitecl in system of communication to oppose a counteracting potentialto' the disturbing poten-.

- tial, a polar relay comprising variable resistance means arranged tobe operated by such relay, means operated by such resistance meanswhereby, as said relay is operated in one direction or another, thefield of the generator is excited in the one sense or the other, andmeans for the control of said relay by the disturbing potential.

3. Means for compensating for potential disturbance in systems ofcommunication comprising a generator connected in the system ofcommunication to oppose a. counteracting otential to the disturbingpotential, a po ar relay comprising variable resistance means arrangedto be operated by such relay means operated by such resistance meanswhereby, as said relay is operated in one direction or another, thefield ing point at which disturbance of earth potential may exist, agenerator in such connection having a controlling field coll, aconductor, other than the mam conductor or I conductors of such systemor systems of communication,'through which current, due

to the disturbance. of earth potential, will flow,. a polar relay havinga controlling magnet interposed in said conductor and having variableresistance means arranged to be operated by such relay, when that relayis operated by current flowing through such v conductor, and meansoperated by such resistance means whereby, as the relay is operated inone direction or another, the fielduf the generator is excited in theone sense or the other.

5. A ground connection for systems of communication comprising aconnection from one point of such system to a grounding point at whichdisturbance of earth potential may exist, a generator in such connection having two opposing field coils, a conductor, other than themain conductor or conductors of such system or systems of communication,through which current, due

-to the disturbance of earth potential, will flow, a polar relay havinga controlling magnet interposed in said conductor, and having twovariable resistance means operated in opposite senses, relatively, bymovements of the armature of said relay, each of said variableresistance means belng 1n circuit with one of the two opposing fieldcoilshof said generator, and a source of current supply connected toboth ofsaid field coils and to said variable resistance-means, whereby,

when saidvariable resistance means are of equal resistance, the saidfield coils neutralize one another, and whereby; as the resistance ofone variable resistance meansis increased, and the resistance of theother variable resistance means is decreased by the action of saidrelay, the one field coil or the-other is-caused to predominate.

In testimony whereof I have signed this specification in the presence oftwo subscribinglwitnesses.

PAUL J. HOWE. Witnesses: 4

H. M. MARBLE, PAUL H. FRANKE.

